Amongst sodium halides (NaF, NaCl, NaBr and NaI), NaF has the highest melting point because of : — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: The melting point of ionic halides is directly proportional to their lattice energy, which represents the strength of the electrostatic forces in the crystal lattice. Step 2: Lattice energy is inversely proportional to the sum of ionic radii of the cation and the anion (r_c + r_a). Since F^- is the smallest halide ion, NaF has the shortest interionic distance. Step 3: This short distance gives NaF the highest lattice energy, resulting in the highest melting point among the sodium halides (option c).